In the specification of U.S. Pat. No. 3,849,405, it is disclosed that some kinds of thieno[2,3-e]-1,4-diazepine compounds possess central nervous actions such as an antidepressive action and an anticonvulsive action. In the specification of U.S. Pat. No. 3,904,641, it is disclosed that a certain kind of s-triazolo[3,4-c]thieno[2,3-e][1,4]diazepine compound has a useful pharmacological activity on the central nervous system such as an antidepressive activity and an anticonvulsive activity.
Meanwhile, as the substances which exist in the gastro-intestinal tissues and central nervous system and which are concerned with the control of the secretion of pancreatic enzymes and gastric acid, known are cholecystokinin (referred to also as CCK) which is a neuropeptide consisting of 33 amino acids and gastrin consisting of 34 amino acids. In connection with CCK, CCK-8 which consists of the 8 amino acids at the C terminus of CCK also possesses the same actions. Also, pentagastrin which consists of the 5 amino acids at the C terminus of gastrin possesses the same actions. The amino acid sequence of pentagastrin is identical with that at the C terminus of CCK.
Since the substances which exhibit an antagonistic action to these CCK and gastrin are effective in the prophylaxis and therapy of such diseases as pancreatic disorders and gastrointestinal ulcers, a number of such antagonistic substances have been studied so far. As an antagonistic substance to CCK, benzotripto is known [Proc. Natl. Acad. Sci. U.S.A., vol. 78, p. 6304 (1981)], and progulmide is known as an antagonistic substance to gastrin, [J. Med. Chem., vol. 27, p. 1597 (1984)]. Their actions are, however, relatively weak, and therefore, compounds having higher activities have been desired.
Besides, peptide antagonistic substances are not altogether satisfactory in that the durability of their actions is short and in that they are unstable and are not absorbed fully.